int n = 10;

int fib(int x){
    if(x == 1) return 1;
    else if(x == 2) return 1;
    else return fib(x-1) + fib(x-2);
}

int main(){
    int a, s;
    a = get_int();
    s = fib(a);
    print_int(s);
    return 0;
}
